// # 过渡计时函数
// 用于控制 CSS 过渡缓和的功能类。
.ease-linear
  transition-timing-function linear

.ease-in
  transition-timing-function cubic-bezier(.4, 0, 1, 1)

.ease-out
  transition-timing-function cubic-bezier(0, 0, .2, 1)

.ease-in-out
  transition-timing-function cubic-bezier(.4, 0, .2, 1)
